terns within images whose compact definitions can
substitute for a full pixel-by-pixel description. To
decompress images, reverse algorithms are used to
reestablish the original pixel structure. Because
some of the original detail will be lost in this
cycle—and some unwanted image ‘‘artifacts’’ gen-
erated—JPEG is counted as a ‘‘lossy’’ compression
scheme (in comparison with the more moderate, but
‘‘lossless’’ compression schemes used in other for-
mats). In general, as higher compression is
employed, more loss occurs.
History
Digital photography has its roots in wire-service
image transmission (a precursor to ‘‘fax’’ technol-
ogy originating in the 1920s), television (which
first used electronic sensors to interpret a lens-
formed light-based image), in unmanned space
exploration (for which computer technologies
were developed that could allow for the conver-
sion of visual data into digital form both for
visual enhancement and for its transmission over
long distances with frequent interruptions), in
satellite espionage photography (requiring exten-
sive image enhancement) and in medical imaging
(which developed technologies for interpretation
and storage of complex visual data). The first
crude computer-controlled image scanners were
developed in the mid-1950s. NASA introduced
digital image processing in the 1960s and trans-
mission in the 1970s. The monitor screen became
the primary computer control interface in the
1970s and was enhanced by graphical user inter-
faces in the early 1980s. The Associated Press wire
service introduced its AP Electronic Darkroom—
a digitally-based image transmission and storage
system—in 1978. These all set the stage for the
rapid development of digital imaging technologies
during the 1980s and 1990s.
The first major photographically-based technol-
ogy to become virtually entirely digital was that of
mass-production offset printing. By the late 1980s,
the vast majority of photographic illustrations
appearing in books and magazines were being cre-
ated by computer-controlled technologies rather
than by traditional photo-process halftone plates.
Large, powerful industrial computers, drum scan-
ners and printing equipment were able to handle the
daunting challenge of creating, handling, and out-
putting millions of bits of digital visual information
well before home computer systems could do so.
Photojournalism was also at the forefront of the
switch to digital technologies. The relatively low
resolution requirements for newspaper photo-
graphs allowed digital capture technologies to be
adopted earlier than in photographic fields with
expectations of higher image quality. Simulta-
neously, the press’s needs for rapid transmission
and distribution of images encouraged develop-
ment of digital transmission systems. By the early
1990s, the marriage of digital capture and portable,
satellite-based digital transmission allowed a news-
paper to put a photograph on its front page less
than an hour after a photojournalist had taken it in
a remote part of the world. Things moved so
rapidly in the industry that most major U.S. news-
papers were closing their darkrooms by the late
1990s (theVancouver Sundescribes itself as the
first to go all-digital, in 1995).
At the broader consumer level, two major mile-
stones would be the 1984 introduction of the Apple
Macintosh system—which brought a visually-
oriented computer to many desktops (usually
equipped with a graphically flexible though low-
resolution printer)—and the 1990 release of the
first version of Adobe Photoshop, the most power-
ful among a number of early ‘‘digital darkroom’’
programs. Photoshop would, in subsequent
releases, go on to become the standard in digital
photography software.
On the ‘‘capture’’ side of the developing technol-
ogies, Sony introduced its first ‘‘Mavica’’ electronic
still video camera in 1981. It wasn’t technically
‘‘digital’’ since it used an ‘‘analog’’ video mini-
disk recording system, but it heralded the move
towards filmless photography. Most major camera
manufacturers developed extensive still video
photographic systems through the 1980s; these
were precursors to truly digital systems. In 1986,
Eastman Kodak introduced the first megapixel
image recording sensor (incorporating one million
individual sensing elements); in 1991 they released
the first professional-level digital SLR, the DCS-
100, incorporating a 1.3 megapixel sensor into a
Nikon-built camera body. The compact Dycam 1
of 1990 was the first truly digital consumer market
camera; it could store 32 compressed images in its 1
Mb of internal RAM and then transfer the images
to a computer.
These technologies offered interesting insights into
the near future, but desktop computing power and
the quality of scanners and printers remained far
from truly photographic. For anything approaching
professional photographic quality, the early 1990s
still demanded expensive computer hardware (such
as Kodak’s half-million-dollar Premier System that
came complete with a high quality drum scanner,
film writer and mini-computer workstation, and
was a relative bargain at the time).DIGITAL PHOTOGRAPHY